Algal Bloom on EARTH Magazine

A new — and more toxic — normal? Harmful algal blooms find new habitats in changing oceans

Fri, 13 Jan 2017 13:06:09 -0500

An Envisat image of a phytoplankton bloom in the South Atlantic Ocean east of the Falkland Islands on Dec. 2, 2011. Chlorophyll pigment detected by ocean-color sensors on Earth-observing satellites can help identify species in algal blooms and their toxicity. Credit: ESA.

In May 2015, a seizure-wracked sea lion hauled itself ashore on a beach in southern Washington. Testing confirmed it was suffering from domoic acid poisoning, an illness that causes disorientation, seizures and sometimes death that stems from the consumption of fish or shellfish contaminated by a toxic species of algae called Pseudo-nitzschia. To the south, in warm California waters where localized toxic blooms of Pseudo-nitzschia are a near-annual occurrence, sea lion illnesses caused by exposure to domoic acid are common — however, this was a first in Washington. The sick sea lion was euthanized, but its stranding in Washington alerted coastal communities to the massive algae bloom that was engulfing coastal waters from Santa Barbara, Calif., all the way to British Columbia.

Iron fertilization foiled by "shrimp"

Thu, 05 Jan 2012 06:41:58 -0500

Researchers sailed to the southwestern Atlantic aboard the RV Polarstern. Alfred Wegener Institute

The argument over whether ocean iron fertilization is a good way to sequester carbon dioxide may be coming to an end. Last month, a group of researchers seeded 300 square kilometers of the southwestern Atlantic Ocean with six metric tons of dissolved iron. Just as researchers hoped, algae bloomed, doubling in biomass within the first two weeks of the fertilization. But then, an unexpected guest showed up: tiny shrimp-like crustaceans that dined on the algae. Therefore, much of the algae — and the carbon dioxide they absorbed — didn’t make it to the deep ocean where scientists had hoped the gas would have been sequestered for hundreds of years.

Toxic tide

Thu, 05 Jan 2012 06:41:58 -0500

A scanning electron microscope image of _Karenia brevis_, the algae responsible for producing red tides in the Gulf of Mexico, and a computer model of brevetoxin that highlights the two reactive sites that bind DNA. Courtesy of John Ramsdell, photo by Karen Steidinger

Algae blooms called red tides lend the water a reddish tint. NOAA

In the Gulf of Mexico lurk menacing masses of single-celled organisms known as red tides. Scientists have long known that the potent toxin they produce can kill fish and birds, wreak havoc on the human nervous system and cause wheezing, sneezing and asthma flare-ups. But new research suggests that it can also damage DNA, which could lead to more subtle, longer-term health consequences.